End effector not goes to desired position

Hello, i am using 2021a matlab release. i am modeling a 3prr delta robot, i made manually inverse kinematics in matlab function and a trajectory planner for end efdector to move in a caertain path, the path of end effector is to go to part position. i give a camera frame, which is constant frame, a frame for moving end effector to track its position points by sensor transform block relative to camera frame and a frame for part which end effector would go to it. i made a 3rd polynomial order that takes end effector position in x y z axis and make it move to part position as xyz points.in path planner block a 3rd order polynomial and inverse kinematics block takes the new position end effector should go to then get the distance desired to move (vertical distance) then give it to the robot. problem is that first end effector position values same as xyz produced from 3rd order polynomial then automatically it starts to have difference which grows this error difference by time till goes to a position not desired and continue with itself. i donot know where is the problem, why do end effector not goes the same points 3rd order polynomial produce?????i would be very thankful if helped me.thanks alot in advance.

[Torsten]

@christina maher comment moved here:

Anyyyyyy help please!!!!!!!

Answer 1

[Rijuta]

Hi Christina,

I understand that you are experiencing a problem with your delta robot not following the desired path that is generated by your trajectory planner. There could be several factors that could be causing this issue, you can follow the steps below to troubleshoot this problem:

• Make sure that your inverse kinematics function is accurately calculating the joint angles required for the end effector to reach the desired position. You can do this by checking the output joint angles against the expected values for a given end effector position.
• Make sure that your trajectory planner is accurately calculating the desired end effector position at each point in time. You can do this by comparing the desired end effector position at each time step to the actual end effector position.
• Make sure that you are not encountering numerical errors, such as floating-point rounding errors or overflow/underflow issues. These can sometimes cause discrepancies between the expected and actual end effector positions.
• Make sure that there are no mechanical issues with your robot, such as friction or backlash, that could be causing discrepancies between the expected and actual end effector positions.
• If you continue to have issues with your current trajectory planner, you may want to consider using a different type of trajectory planner, such as a cubic spline or a quintic polynomial, to see if this improves the accuracy of your end effector positions.

I hope this helps you solve your problem.